# -*- coding: utf-8 -*-
"""
@Time ： 2020/10/26 10:09
@Auth ： Mr. JJ_Cloud
@Company ：testingedu.com.cn
@Function ：函数和文件
"""

from sys import argv
script, input_file = argv

def print_all(f):
    print(f.read())

def rewind(f):
    f.seek(0)

def print_a_line(line_count,f):
    print(line_count,f.readline())

current_file = open(input_file)

print("First let's print the whole file :\n")

print_all(current_file)

print("Now let's rewind,kind of like a tape.")

rewind(current_file)

print("let's print three lines:")

current_line = 1
print_a_line(current_line,current_file)

current_line = current_line + 1
print_a_line(current_line,current_file)

current_line = current_line + 1
print_a_line(current_line,current_file)